Coronary artery disease, myocardial infarction, stroke, and other vascular occlusions are major health concerns. A common characteristic of these diseases is the atherosclerotic process, or the narrowing of arteries. Blood platelets contribute to the development and progression of the atherosclerotic process by releasing growth factors, chemotactic substances and other factors that accelerate the atherosclerotic process. In addition, platelet aggregation at or near the point of arterial damage contributes to the development of atherosclerosis and acute platelet thrombus formation.
Low density lipoprotein (LDL) cholesterol is also associated with atherosclerosis. It has been proposed that nonatherogenic LDL cholesterol circulating in the blood is converted to atherogenic LDL cholesterol through oxidation of polyunsaturated lipids, which leads to modification of the apoprotein.
Physicians use various drugs, such as aspirin, to treat atherosclerotic conditions. Aspirin, however, is not without negative side effects including gastrointestinal irritation. Interventions such as angioplasty are also available to dilate stenosed arteries thereby increasing blood flow. Interventional techniques, however, produce intimal and medial artery damage and expose thrombogenic surfaces. As such, restenosis and the incidence of sudden coronary death following angioplasty is a major concern for patients with known or suspected coronary artery disease.
Given the grave consequences of atherosclerosis and the costs associated with medical treatments, there is a need for pharmacologic and nutritional interventions that are useful for preventing the occurrence and reoccurrence of these conditions.
Epidemiological studies have noted an inverse correlation between the intake of dietary flavonoids from fruits and vegetables and death from coronary artery disease. This correlation is thought to arise from the antioxidant and platelet inhibition properties of flavonoids found in fruits and vegetables.
Certain flavonoids, including those found in grape seed and grape skin extracts, have been associated with the beneficial health effects observed for aspirin, but without the negative side effects attributed to aspirin. Nevertheless, flavonoid bioavailability or activity is low in many sources of flavonoids. As such, certain dietary sources of flavonoids require large doses to be useful. As a result, many sources of flavonoids are impractical, too costly, or both to be useful on a daily basis.